Envelope fastener



June 2, 1959 TfA. CROSSLEY 2,889,105

ENVELOPE FASTENER Filed March 5. 1957 ATTORNEYS.

United States Patent 2,889,105 Patented June 2,. 1959 This invention relates to an envelope fastener, and more specifically, to an improved fastener for securing the ap of an envelope in closed or folded position.

One of the objects of the present invention is to provide an improved fastener for envelopes having a pair of normally parallel and adjacent spreader elements which may be easily expanded by exerting a force against their free ends in a direction towards the fold line of the envelope ap; that is, towards the opening of the envelope. In this connection, it is a specific object to provide the spreader elements with upwardly curved free ends so that the elements or arms may be easily folded into llapsecuring positions by movement of an operators finger in a single direction against both elements, the curved tips also serving to frictionally engage the envelope Hap when the arms are in expanded or flap-securing positions. Another object is to provide a fastener having spreader elements which tend to engage the closure flap of an envelope more tightly in response to forces tending to draw the llap along the envelope body and into open position. A further object is to provide a fastener having a body portion which will not twist upwardly away from its connection with the envelope body in response to forces which tend to urge the closed ap along the body of the envelope and into open position. A still further object is to provide a highly effective envelope fastener of compact construction which may be die cut from a sheet of suitable material with a minimum of waste or scrap material formed during the cutting operation.

Other objects will appear from the specification and drawings in which: Y

Figure l is a broken plan view of an open envelope equipped with a fastener embodying the present invention; Figure 2 is a broken plan view similar to Figure l but showing the envelopes ap in closed position; Figure 3 is a top plan view of the envelope fastener in a preliminary stage of its manufacture after it has been cut from a sheet of material; Figure 4 is a top plan View of `a completed fastener; Figure 5 is a broken sectional side view of an envelope equipped with a fastener, the spreader elements of the fastener being partially expanded -or raised; Figure 6 is an enlarged broken side sectional view taken along line 6--6 of Figure 2; and Figure 7 is an enlarged broken transverse section of an envelope flap held in closed position by a fastener embodying the present invention, the view being taken along line 7 7 of Figure 6.

Referring to the drawings, the numeral 10 generally designates an envelope having a body 11, an opening 12 .and a closure ap 13. The ap is foldable between open and closed positions (Figures 1 and 2 respectively) along a line extending along one edge of the envelope and provided with a circular opening 14 having its periphery reinforced by a perforate disk or ring 15 adhesively secured to the flap. Since the construction of the envelope is entirely conventional, a more detailed description is believed unnecessary for the purpose of disclosing the present invention. The envelope itself may be formed of paper, cloth or any other suitable material.

As shown most clearly in Figure 4, the fastener 16 has a body 17 equipped with a pair of lateral portions 18 and a pair of spreader elements or arms 19 formed integrally with the body. The arms are normally disposed adjacent each other and extend in the same direction away from the central portion of the fastener body. The outer edges of the arms have complementary convex curvatures while the inner opposing edges are straight and are preferably separated 'by a straight slit or cleft 20.

In the illustration given, slit 20 terminates in a circular opening 21 intermediate the later portions 18 of the fastener.

The fastener may be formed of any suitable sheet material such as steel, brass, etc. In the die cutting operation, the lateral portions are provided with intersectingslits 22 (Figure 3) and then, in the same or in a subsequent operation, the triangular prongs 23 defined by these slits are turned downwardly at right angles to the plane of the fastener. Later, when the clasp is mounted upon the body of an envelope, the pointed prongs 23 are driven through the wall of the envelope and are again turned to clamp the envelope wall between the edges of the lateral portions 18 and the prongs 23. lt is to be noted that the fastener is secured to 'the body of the envelope with the adjacent arms 19 extending away from the fold line of the flap 13 and in longitudinal alignment with the opening 14 provided by that ap. Arms 19 and opening 14 are equidistant from the flaps transverse fold line so that when the closure ap is folded into closed position opening 14 will be disposed directly above the arms or spreader elements.

Arms 19 are foldable along a pair of fold lines represented by dotted lines 24 in Figure 4 which extend at substantially right angles to each other and which are angled at substantially 45 degrees with reference to the longitudinal mid-line of the fastener extending along slit 20. Each fold line extends between the edge of circular opening 21 and a juncture between the curved outer edge of one of the arms and the edge of the lateral portion adjacent thereto. To dene the fold lines and to rigidify or strengthen the foldable arms, each of the arms may be provided with a dished-out or embossed portion 25, the borders of the embossed portions being spaced from the edges and from the fold lines of the spreader elements or arms.

Preferably, the spreader elements are provided with curved end portions 26 which turn upwardly away from the body of an envelope when the elements are in their normal or unfolded positions shown in Figures 1 and 4. 'llhese upwardly curved end portions facilitate the folding of the arms into flap-securing positions, as will be described shortly, and also frictionally engage the envelope flap to hold it tightly in closed position, i.e., in parallel overlapping relation with the envelope body (Figure 7).

In the operation of the structure embodying my invention, the fas-tener is first mounted upon the body of an envelope in the manner previously described. After the envelope is filled, ilap 13 is folded into its closed position wherein the adjacent arms 19 are disposed directly below circular opening 14. To secure the ap in closed position, the upwardly curved end portions 26 of the arms which project above the apertured flap are simply urged away from each other and towards the fold line of the flap. Folding action of the arms may be achieved by simply moving an index finger or thumb against the upturned ends of the arms and along the mid line of the fastener in a direction towards the opening 12 of the envelope. The angled fold lines 24 direct the folding movement of the arms upwardly 3 and outwardly so that when the arms are in liap-sen curing positions they will be disposed above lateral portions 18 with 'the envelope iiap disposed therebetween. Hence, in a single operation the paired spreader elements may be simultaneously folded into hap-securing positions.

When the spreader elements have been folded, the curved points or end portions 26 of the elements tend to bite into the outer surface of the ap and hold it securely in closed position. In addition, movement of the flap is prevented by engagement between the portions of the fastener at the junctions of `the arms curved edges and edges of the lateral portions. In other words, the edge portions ofthe fastener adjacent the ends of the fold lines engage the edge portions of the tlap about opening 114 and prevent movement of the flap along the body of the envelope and in a direction towards opening 12 because of the diminishing vwidth of the opening resulting from its circular configuration.

Furthermore, since the laterally projecting arms are folded along lines which extend downwardly towards the bottom edge of the envelope and away from theenvelopes central or longitudinal midline, any force which urges the liap along the body and towards the opening 12 will tend to bend the foldable arms into tighter engagement with the flap, thereby increasing the frictional engagement between the opposing parallel surfaces of the flap and body, rather than to urge the arms back into their unfolded or normal position. Consequently, the

fastener of the'present invention provides a secure interlock between the body and foldable flap of an envelope and securely maintains the Hap in parallel, overlapping relation with the envelope ibody despite forces tending to slide the ap in an open position.

It will be noted that the fold lines 24 of the fastener are disposed between the spaced lateral portions which connect the fastener to the envelope body and that these lines do not extend longitudinally (with reference to the envelope) beyond those portions. In other words, the 'highest points of the fold lines are below the upper edges of the lateral connecting portions, and similarly, the lowest points of the fold lines are no lower than the lower edges of those portions. As a result, forces which tend to urge the ap longitudinally along the body of the envelope will not operate to lift or twist the lateral portions 18 away lfrom t-he envelope. Thus `the orientation of the fold lines between the paired lateral connecting portions 18 contributes to the effectiveness of the present structure in maintaining a secure interlock between the body and iiap of the envelope.

While in the foregoing I have disclosed an embodiment of my invention in considerable detail for purposes of illustration it will be understood by those skilled in the art that many of these details may be varied considerably without departure from the spirit and scope of the invention.

I claim:

l. ln combination with an envelope `having a body and having top closure flap provided with an opening therein and adapted to be folded into a closed position over a portion of said body along` a fold line extending along an upper edge thereof, a fastener for securing said liep in closed position comprising a fastener body having spaced lateral portions secured to said envelope body, a pair of spreader elements formed integrally with said fastener body and normally disposed in adjacent parallel relation extending downwardly away from the upper fold line of said flap, said elements being foldable along angled fold lines into flap-securing positions wherein said elements extended through said iap opening and project laterally in opposite directions upon said Hap, said angled fold lines being disposed'between the spaced lateral portions of said fastener body and within the limits of the upper and lower edges thereof.

2. A fastener lfor securing a flap at the top of an envelope in closed position comprising a fastener body having a pair of spaced lateral portions adapted to be secured to the body of an envelope, arid a. pair of spreader elements hingedly secured to said fastener body along outwardly and downwardly diverging fold lirios disposed between said lateral portionsi said spreader elements being normally disposed adjacent each other and extending in the same direction downwardly away from the opening of an envelope, said spreader elements being foldable along said angled fold lines into Hap-securing positions wherein said elements extend outwardly in opposite directions, said diverging fold lines having their lower ends no lower than the lower edge of said spaced lateral portions.

References Cited in the fileof this patent UNITED STATES PATENTS 558,823 Logan Apr. 2i, 1896 885,884 Stimpson Apr. 28, 1908 1,105,431 Hodgson 'Y July 28, 1914 1,474,876 Andrews Nov. 20, 1923 2,325,702 Noviok Aug. 3, 1943 

